The invention relates to a device for providing fresh air to the passenger compartment of a vehicle having a hood, comprising a filter device arranged on a back of the hood and connected with an air collecting chamber in a front wall area of the vehicle, a blower arranged to aspirate and convey air to air outlet openings terminating in an interior portion of the vehicle, and fresh air intake openings are provided in the hood at a level of the filter device.
DE 39 23 307 A shows a device in which the fresh air is aspirated in the forward area of the vehicle and is brought to the front side via air guide conduits integrated into the hood. A filter device is provided inside the hood, and is accessible when the hood is opened and a cover plate removed.
The disadvantage in this known device is that the entire hood is used for the guidance of the air. Consequently, a minimum height is required, which can be realized only with difficulty at all points of the hood.
U.S. Pat. No. 3,157,104 shows another device for providing fresh air to the passenger compartment of a vehicle. Here, the fresh air is conducted via two separately disposed fresh air intake openings into a pressure compensation chamber from where it flows, separated into two separate flows, via two filters into an air collecting chamber, from where a blower conducts the cleaned fresh air to air outlet nozzles in the interior of the vehicle. The pressure compensation chamber ahead of the filters is used to even out the possibly different mass flows entering via the two fresh air openings.
The disadvantage in this arrangement is that coarse dirt and water can reach the filter surfaces and block or moisten them. As a result, the flow-through resistance of the filter will rise rapidly so that sufficient amounts of fresh air no longer can reach the passenger compartment. This is particularly disturbing in wet weather, because in that case the windshield has a particular tendency of becoming fogged on the inside and then can no longer be sufficiently dried.
It is an object of the present invention to provide a small-dimensioned, maintenance-friendly and effectively operating fresh air supply with a filter device.
This object has been attained in accordance with the invention by providing that the fresh air flow is divided into two partial flows after passing the fresh air intake openings and the two partial flows are brought to two filters, such that the partial flows are guided around the filters and flow upwardly therethrough, and the cleaned fresh air is separately guided from each of the filters into the common air collecting chamber. The distribution of the fresh air flow aspirated via the common fresh air intake openings to two filter devices reduces the structural space required by the air guidance inside the hood and permits the optimum utilization of the structural space provided, so that it is possible even to use filter devices of different sizes. A pressure compensation then takes place in the common air collecting chamber ahead of the blower. Because of this configuration, the flow of the not-yet cleaned air is reversed several times, so that coarse dirt and water can be effectively removed. It is assured thereby that the surfaces of the filters remain free of liquid so that the flow resistance only is slowly increased as a result of aging.
A further advantageous feature of the present invention is that liquids carried along are removed and are kept from reaching the filters.
Still a further advantageous aspect of the present invention is that the structural outlay for the fresh air guidance is simplified in that it is not necessary to provide a multitude of guide plates. This is achieved instead by separate housings which are inserted into the filter device.
Depending on the distance of the hood from the area of the front wall of the vehicle in which the air collecting chamber is located, guide conduits can be provided on the front wall for conducting the cleaned fresh air from the filter device to the air collecting chamber.
Water or other objects are prevented from penetrating into the air collecting chamber when the hood is opened by closing the inlet openings into the guide conduits by hinged flags which are actuated by guide devices on the filter device. Entry of water is a particular threat when the vehicle is a vehicle with a front engine and engine cleaning is performed.